1. Field of the Invention
The present invention relates to a three-wheel vehicle provided with a swinging mechanism, which reduces costs and enhances ride comfort.
2. Description of the Related Art
A three-wheel vehicle provided with a swinging mechanism in which right and left rear wheels are coupled via a shaft is known. For example, Japanese published examined patent application No. Sho58-24310 discloses such a vehicle. FIG. 19 is a side view showing a conventional type three-wheel vehicle (such as shown in Japanese published examined patent application No. Sho58-24310) provided with a swinging mechanism. A front frame 202 provided with one front wheel 201 and a rear frame 205 provided with right and left rear wheels 203, 204 are coupled via a pivot coupling device 206.
The pivot coupling device 206 is composed of a housing attached to the front frame 202 and a pivot the front of which is rotatably attached to the housing and the rear of which is attached to the rear frame 205, and the front frame 202 can be rolled around a pivot axis 207 for the rear frame 205.
FIG. 20 is a sectional view showing the rear of the conventional type three-wheel vehicle provided with the swinging mechanism and shows that one end of an intermediate shaft 212 is connected to a rear wheel shaft 211 to which one rear wheel 203 is attached via splines, the other rear wheel shaft 214 is attached to the other end of the intermediate shaft 212 via friction differential gears 213 and the other rear wheel 204 is attached to the rear wheel shaft 214.
As shown in FIG. 19, the three-wheel vehicle is provided with the pivot for swinging the front frame 202 crosswise, however, the three-wheel vehicle is provided without a swinging shaft for vertically swinging the rear wheels 203, 204. When such a swinging shaft is provided, the number of parts is increased and the cost is increased.
As the right and left rear wheels 203, 204 are integrated via the rear wheel shaft 211, the intermediate shaft 212 and the rear wheel shaft 214 as shown in FIG. 20, the rear wheel 203 is lifted upward when one rear wheel 203 runs on a convex portion of a road, for example. The effect is transmitted to the other rear wheel 204 via the rear wheel shaft 211, the intermediate shaft 212 and the rear wheel shaft 214, the rear wheel 204 is inclined, the rear frame 205 shown in FIG. 19 is rolled and the front frame 202 is vertically moved by the roll. Such configuration causes little trouble in a vehicle when the displacement is small; however, when the displacement of which is moderate or high and if the vehicle is moving quickly, an improvement in ride comfort is desired.
The swinging shaft is separately provided on the right and on the left. A swing arm is respectively attached to these swinging shafts and the rear wheels 203, 204 are attached to these swing arms. Thus, the right and left rear wheels are made independent and the vertical motion of one of the rear wheels 203, 204 has no effect upon the other. However, since the swinging shafts are provided to the right and the left, the cost is increased.
An object of the invention is to reduce costs and provide enhanced ride comfort for a three-wheel vehicle provided with a swinging mechanism.